Re: [CAD_CAM_EDM_DRO] Re: Lead screw/Guide rail install/pre-load

Hi Hugh,

I'm sure it would work but the biggest problem I can see is the need for
moving cables. These will inevitable wear in the long run and will
certainly get in the way. It may even be that the extra you need to spend
on ways of controlling these cables - sheathing, supports, more flexible
cable etc., would be more than the cost of the couple of bearings for the
leadscrew - you would, of course, still need exactly the same leadscrew
which is the major expense.

Ian
--
Ian W. Wright
Sheffield UK

----- Original Message -----
From: "Hugh Mahlendorf" <hmahl@...>
To: <CAD_CAM_EDM_DRO@egroups.com>; <CAD_CAM_EDM_DRO@egroups.com>
Sent: 27 October 2000 01:53
Subject: Re: [CAD_CAM_EDM_DRO] Re: Lead screw/Guide rail install/pre-load


>
> >Just a suggestion:
>
> I was looking through a catalog earlier today and found stepper motors
that
> have internal through threads on the armature of the motor so that a
> leadscrew (will get more particulars on this tomorrow) can be fixed at
both
> ends and the motor fixed to the table, letting the stepper do the turning,
> thus "crawling" back and forth on the lead screw. This would eliminate
all
> mounting bearings and also eliminate the need for intermediate leadscrew
> support (the motor in effect becomes the support). One motor (probably a
> NEMA 42) mounted on the underside of the movable table in the x and y
> center would control the x movement without racking.
>
> Any reason this wouldn't work? I suppose the stepper would be kinda
> expensive but would'nt it still be cheaper than all the bearing supports
> mentioned earlier.
>
> If I am missing something, please let me know as this is the type of table
> I am contemplating on my small CNC router.
>
> Hugh
>
>
> >I'm doing what is essentially a 3 axis router: 48" x 36" x 18" of
> >cutter travel. It'll have the z-y plane fixed in x, with a
> >travelling x table moving below the y-z plane.
>
>
>
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